low value, meaning it is already listed on an exchange and has a very low price. I sell it more often because most of the altcoin prices obtained from bounties or airdrops will decrease over time. However if the altcoin obtained has not been registered on the exchange, there is no other choice but to hold.
Yes selling of coins which you have received from bounties is a good step because as more people sell these tokens the price of it gets reduces and there are large number of other participants in bounties too that prefer to sell these tokens on time and when you failed to sell immediately then you will face trouble in selling it. If the price is too low that it cannot give you some money then hold it because now there is no other choice with you. Many people hold coins for longer time but there is a 20% chance that these tokens will grow in future but 80% possibility exists for declination in price which suggests that the chances of losing more value in future is greater than its growth.